Seam gauges or guides have been used by sewing machine operators for many years to assist in forming seams of uniform width from the edge of sewn fabric. An example of a conventional seam guide is shown and described in U.S. Pat. No. 968,346. The guide is secured by a bolt and nut combination to the bed plate of the sewing machine and is adjustable transversely by the operator to control the width of the seam from the edge of the fabric. The seam guide is supported on the bed plate by a slotted flat member clamped to the bed plate by tightening the nut on a bolt or stud, the bolt projecting upwardly from the bed plate through the slot in the flat plate. To adjust the seam gauge, the nut is loosened which allows movement of the flat plate transversely of the needle with the threaded stud projecting upwardly through the slot in the flat plate. When a suitable location is found for the seam gauge, the nut is retightened to hold the seam gauge rigidly in position.
This hand operation, as described in U.S. Pat. No. 968,346, is time consuming and in commercial operations it may present an undesired obstruction in the area between the needle and the sewing machine support standard. Often it is desired to turn fabric being sewn to change the direction of the seam by an angle up to 90.degree.. When that occurs the already sewn material or the trailing portion thereof may be turned into the vacant space between the needle and the sewing machine support standard. In order to do this, the seam guide must be removed to prevent the fabric from snagging.
An additional problem is the time it takes to adjust the spacing of the seam guide from the needle. For example, in many commercial operations the width of the seam may be 1/4 inch or one inch (0.6-2.5 cm) and repetitive sewing operations may require a shift from one width to another to perform the desired sewing operation. With the hand operation described above in U.S. Pat. No. 968,346, the bolt or nut must be loosened, the seam guide shifted to the proper width and the bolt retightened every time a seam is sewn. The need for a fast and easy automatic spacing apparatus is obvious.
U.S. Pat. No. 2,977,908 makes an attempt to mount and remove a seam guide by pneumatic apparatus but it is highly cumbersome to operate and the apparatus is somewhat complicated. What the disclosed apparatus does not do is remove the seam guide from between the needle and the standard to provide an unobstructed flat surface for the manipulation of previously sewn fabric which may be rotated into that flat area. It does have a piston and cylinder combination to operate in combination with a lever for pivoting a guide into place and out of place. The guide pivots about a vertical axis rigidly secured to the upper surface of the bed plate.
The U.S. Pat. No. 3,020,864 discloses two pivotal seam guides which are both mounted on a bracket secured to a presser foot bar. Both seam guides comprise a bar and a flat blade projecting transversely from the presser foot bar toward the sewing machine head mounting standard and downwardly toward the bed plate. In order to adjust each of the seam gauge bars a set screw is loosened and the bar set to the desired spacing; in the example above, one could be spaced at one half inch (1.3 cm) and the other at one inch (2.5 cm) from the needle. In order to move the two seam gauges out of the area between the needle and the sewing machine support standard, the two seam gauges are pivoted upward toward the operator of the machine, thereby providing an obstructed flat surface for the rotation of the sewn fabric. The problem is that each of these blades forming the seam guide is tremendously dangerous to the operator who might bend forward and jam one of the blades into her face or her eye. As a result the proposed apparatus is totally unsuitable for sewing machine operations. It solves one problem but creates another which is completely unacceptable.
U.S. Pat. No. 3,875,881 discloses a separating guide for fabric layers in combination with a seam guide to be mounted on a bed plate intermediate the sewing machine needle and the standard supporting the sewing machine head. The seam guide disclosed in the patent does not move. But the two fabric separating plates are mounted to slide back and forth toward the needle and the movement is effected by a pneumatic piston and cylinder combination. The patent does not disclose, but it is obvious that the seam gauge could be reciprocated by the same piston and cylinder combination. What the disclosed structure does not do is provide a mechanism automatically operated to set and remove the seam guide from within the work area when it is unnecessary for conventional operations.
What is needed is a seam guide which may be conveniently and quickly removed from the work area when necessary and reinstalled at a specific spacing with respect to the sewing machine needle by the operator with a minimum of time and effort. It is further desirable to have a piece of apparatus which can be adjusted by the operator with a minimum of time and effort at a plurality of preset spacings.